If you’re unfamiliar, the Dunning-Kruger Effect is the name of a cognitive bias where people consistently rate themselves as being higher skilled than others, even (especially?) then they are decidedly not. In other words, people are nowhere near as good as they think they are.
Diametrically opposed to that is Impostor Syndrome, where people refuse to acknowledge their accomplishments and competencies.
If you’re aware of both of them, you might constantly vacillate between them, occasionally thinking you’re awesome, then realising that it probably means you aren’t, going back and forth like a church bell. I know nothing of this, I assure you. But the point is that I think they’re almost certainly related to the people that we surround ourselves with.
Look at it like this. Suppose you stumble into photography somehow. You like taking pictures, and so you do it a lot. Over time, you start to notice that some of your pictures appeal to you more than others. You like them more, and you decide that they’re better than the others, so you take more pictures like them. Over time, your portfolio grows and you begin to get to the point where almost all of the photos you take are good, in your eyes.
Thus far, there is no problem.
Suppose then, that you decide you want to start a photography business. Now, we have the beginnings of a problem. Are your photos good, or have you decided that they’re good? Are they good enough to sell? You don’t know. But notice through that description that I never once said that you looked at other people’s photographs. You never studied Ansel Adams or any of the people that came before or after him. You didn’t join a community and discuss photography. You just did it, and that’s awesome. But when you start to do it professionally, there is a big change. Someone is paying you for skills, and unless you’ve worked to acquire those skills, you don’t have them. In this case, you might not even know they exist.
The photographer in question might very well be determined to have Dunning Kruger. Not only do they not have skills, they don’t know that the skills they need even exist!
Now, lets suppose you (the photographer), in the course of looking into how to start a photography business, see some pictures that catch your eye. They’re kind of similar in terms of style to yours, but they’re better. Way better. So you research the photographer who took those, and you dive in deep. It’s like a gateway drug, and you come up for air six months later in an art museum somewhere in Brussels, and you have had a revelation. You suck.
You decide that you want to not suck any more, so you take photography classes, you join local photography groups. You take lots of pictures, you exchange stories and tips and you learn with each other. But something is wrong. The more you learn and practice, the better your pictures get, but the more you think you suck. You look at other people’s photography and recognise it a being amazing when it is, in fact, amazing, but you’ve lost objectivity to your own work. You compare it to the masters of the art, because you now know about the masters of the art, and you realise that your skill level doesn’t even come close. You might academically recognise that your pictures are far superior to what you used to take, and that even though you’ve placed in some photography contests in the past couple of years, you just don’t stack up against everyone else and you see yourself as a failure, despite your successes.
You now have Impostor Syndrome.